1. Argo is such a terrific, jaw-dropping true-life tale, with such a natural, seamless movie storyline, that anyone who knows the story would beg the filmmakers not to screw it up. So it's a relief that they absolutely do not do that. There are so many tones to juggle here; this is a film that veers from political drama to Hollywood insider comedy to riveting thriller and then back again. It would have been so easy to err. This material required, and had, a steady hand at the till, a director who would understand that the job here is just to hit all the right notes at just the right times and otherwise stay out of the way. That that director is Ben Affleck, of all people, is somehow even more perfect: It's a project that any director on earth would want, and that he not only got it but nailed it feels oddly right. This is a movie that absolutely knows what it's doing.

2. The movie is based on the true story—told most memorably in this fantastic Wired story—of Tony Mendez, a CIA agent in 1980 charged with trying to help six Americans escape from Tehran during the U.S.-Iranian embassy crisis. With the amount of time to rescue them dwindling—they fled the embassy during the raid and have been living for months in the home of the Canadian ambassador—Mendez comes up with a whackadoodle plan to pose himself and the six people as a film crew making a cheesy Star Wars knockoff called Argo. That's the whole plan: We watch as Mendez (played by Affleck) works with the CIA, the Canadian government, the White House and, most memorably, two Hollywood producers (played, hilariously, by John Goodman and Alan Arkin) who help him firm up his backstory. The first half of the film is about Mendez figuring out his plan; the second half is about the execution.

3. This is essentially a heist film, and Affleck directs the shit out of it; every moment is wrung out for every last drop of tension. I'm not sure how Affleck became such a muscular director, but the guy understands story structure and how to maximize audience manipulation at every moment. He has a lot of fun with the Hollywood scenes—Arkin steals the film as a sleazy film producer who hangs out at his pool in his shorts all day but whose bluster hides a deeply patriotic and noble soul—but, as in The Town, Affleck is at his best when he's making a simple story feel huge and epic and grand and brawny. (I think it's all the overhead establishing shots; these are as vital to Affleck as an atrial valve, and they work every time.) The last 45 minutes of this film, as our heroes encounter obstacle after obstacle after unexpected snag, are almost unbearably tense. It's virtuoso work: Affleck has a strong, pulsating professionalism in him that betray the fact that he's only directed three films. Honestly, this is a guy who could direct the next Batman film. It'd feel like Die Hard with a cowl.

4. Unfortunately, Affleck would probably cast himself, and that's where Argo keeps getting hung up. Affleck isn't a bad actor, necessarily, just an inscrutable one; behind the camera, he makes everything feel real and raw, but in front of it, his performances always have an undeniable dash of posing to them. It feels like he plays Ben Affleck, Movie Star rather than whatever character he's assigned himself. Mendez is a likable character, but Affleck doesn't give him much life other than "patriotic warrior." (It's also worth nothing that we never get a major sense of Mendez's ability to improvise the way the Wired story explained; Affleck is too busy playing Stoic, Calm Protagonist.) Affleck's on screen almost the entire movie, but less as a live human being and more as a tour guide through the movie's plot. It's necessary for the story, but it would have been nice if Affleck had found an actor who could breathe more life into this guy, who could make him feel as uncertain and terrified as he surely was. Affleck also gave Mendez a family subplot that gets in the way of anything else; he tries to make us feel an emotional involvement when we don't really need to. We're too busy spending the last 45 minutes biting the arm of the person sitting next to us.

5. There's something undeniably stirring about the film, regardless; it seems old-fashioned to have a movie in which the good guys win thanks to international cooperation, the honor of diplomatic borders, and some good ole' rollin'-up-the-sleeves American know-how. (Bryan Cranston plays a CIA staffer working with Mendez who tries to keep the bureaucracy of government off his back.) The movie is a big-hearted, full-throated, expertly made crowdpleaser, produced with skill, wit and a seriousness of purpose. With this, Gone Baby Gone and The Town, Affleck has revealed himself, amazingly, as one of our most talented mainstream filmmakers. (He just needs to stop choosing himself for his cast.) Argo isn't perfect, but its flaws don't really matter: This is premium, breathless entertainment.

Grade: A-.

Grierson & Leitch is a regular column about the movies. Follow us on Twitter, @griersonleitch.